| A | B |
|---|
| ray | a line with and endpoint |
| angle | two rays with a common endpoint |
| vertex | The common endpoint in an angle |
| acute angle | an angle less than 90 degrees |
| obtuse angle | an angle greater than 90 degress but less than 180 degrees |
| straight angle | an angle that is 180 degrees |
| right angle | an angle that is 90 degrees |
| complementary | two angels that the sum of their measures is 90 degrees |
| supplementary | two angle that the sum of their measures is 180 degrees |
| congruent | two angles that have the same measure |
